Oil reservoir for hydraulic equipment



Jan. 27, 1959 J. s. SCHROEDER OIL RESERVOIR FOR HYDRAULIC EQUIPMENT Filed June 8, 1954 INVEN TOR. John .S. Schroeder 2,870,786 OIL RESERVOIR FOR HYDRAULIC EQUIPMENT John S. Schroeder, Edgeworth, Pa., assignor, by mesne assignments, to Schroeder Brothers Corporation, Pittsbu g Pa-, a corporation of Pennsylvania Application June 8, 1954, Serial No. 435,111

1 Claim. (Cl. 137-587) This invention relates to improvements in an oil reservoid and particularly to one adapted for mobile hydraulic equipment which is subject to tipping and is used in locations having low headroom.

Hydraulically operated equipment is very commonly used in coal mines because of its flexible operation. Such a,system includesa reservoir primarily to cool the hydraulic fluid which becomes considerably heated in use and to accommodate surging. V

When a reservoir is used in a restricted area such as a coal mine, certain design requirements are much more accentuated. For instance, since space is at a premium,

the reservoir should be as small as possible to occupy a minimum amount of height without sacrificing efliciency. This, in turn, means that there should be no dead areas within the reservoir but rather a continuous flow of all portions of the oil through the reservoir. With restricted headroom and consequent reduced tank height the possibility of the tank being tipped makes the usual tank design, of opposing inlet and outlet ports with baflfles between them to lengthen the flow of oil, highly impractical because the outlet must not rise above the oil level and in use tanks are not always filled to capacity.

In any oil tank or reservoir, it is important that oil which is fed into the tank shall not be discharged into air within the tank, since air is thereby trapped in the oil which flows out of the tank and impairs the operation of machinery driven by the oil. All oil tanks or reservoirs must be vented, with the result that there is always a certain amount of air within a tank. In a relatively nited, States Patent ice .2' The accompanying drawing illustrates a presently 'pre* ferred embodiment wherein: I

Figure l is a plan view of my reservoir with thetop plate removed;

low tank, the problem of preventing discharge of oil into air within the tank is increased, particularly if the tank is tilted during use as is frequently the case with tanks used on mining machinery.

Finally, the maximum cooling of the oil must be effected with the minimum amount of cooling area.

The present reservoir meets all of these requirements. My reservoir includes a small flat tank in which the return oil is discharged from a return pipe in the tank in small streams into the oil within the tank. The outlets for the streams are spaced from the sides of the tank and directed toward the side walls where the oil is cooled by contact with the walls. The streams circulate the oil throughout the tank and induce a flow of oil along the bottom of the tank toward the center thereof. In this manner, all of the return oil passes in and out of the tank and there are no dead areas. Also, the maximum amount of cooling is realized in that the return oil strikes the coolest part of the tank at the side walls where the absorbed heat is quickly radiated. The entrance to the outlet pipe is placed in the center of the tank and above the bottom so that sludge and impurities are not returned to the pump. The entrance to the outlet pipe and an air vent are also located at the center of the tank to allow substantial tilting of the tank without interference with its operation.

Figures 2, 3, and 4 are sections of Figure 1 on the lines IIII, III-III, and IV-IV, respectively; and

Figure 5 is an enlarged fragmentary partiof Figure 4 showing a vent for the tank.

Referring to theidrawing, my reservoir includes a tank 10 which comprises top and bottom plates 11- and. 12 joined by side walls 13. Posts 14 reinforce theplates and a clean-out plate 15 is bolted to one of the side walls. Holders 16 fix a return pipe 17 to the bottom .plate 12. The return pipe 17 follows the periphery of the bottom plate but is spaced therefrom. One end of this pipe projects through a side wall, terminating in a coupling 18 for connection to a return line from operating machinery. The other end of the pipe 17 is sealed. A plurality of openings 19 are spaced along the pipe and are sized to get a relatively even distribution of oil. These openings are directed toward the side walls and preferably are in the upper half of the pipe 17 and make an angle with the horizontal for reasons hereafter described.

An outlet pipe 20 extends from the center of the tank 10 through a side wall, terminating in a coupling 21 for connection to a supply line. The entrance to the outlet pipe 20 has a cap 22 comprising superposed slates 23 and 24 supported by legs 25 which insures withdrawal of oil from all directions. A holder 26 fixes a vent pipe 27 to the top plate 11. As shown in Figures 4 and 5, the pipe 27 has an elbow 28 carrying a fitting 29 which is placed adjacent the top plate 11 at the center of the tank. The fitting has slots 30 to reach the tank atmosphere and, at the same time, provide as high an oil level as possible. -It is preferred to vent the pipe 27 laterally of the tank through a side wall as shown rather than through the top of the tank. This construction eliminates a dust cap on top of the tank which would increase the overall height of the tank. The tank also has a filler pipe 31 and cap 32.

In operation, oil returning to the reservoir flows into the pipe 17 and out through the openings 19. The openings 19 are tilted upwardly, making. an angle of 15 with the horizontal, with the result that oil passing through the openings flows both upwardly and outwardly towards the side walls of the tank. The flow of oil then passes upwardly along the walls and then along the top of the tank to the outlet pipe 20. The oil is cooled by contact with the side walls of the tank and all of the oil within the tank is circulated. There are no dead spots to reduce the efficiency of the tank.

It should be noted from the drawings that the pipe 17 is spaced a substantial distance from the side walls. This promotes an even flow of oil. If the pipe 17 were spaced close to the side walls, the oil would splash against the side walls and churn around the pipe 17 and between it and the side walls.

It should also be noted that since the opening to the outlet pipe 20 and the opening of the vent pipe 27 are in the center of the tank, the tank can be tilted to a substantial angle without interfering with the operation.

While the foregoing disclosure describes a presently preferred embodiment, it is understood that the invention may be practiced in other forms within the scope of the appended claim.

I claim:

An oil reservoir for a closed hydraulic system and the like including a tank, a pipe for receiving oil returned to the tank positioned on the bottom of the tank and Patented Jan. 27,

substantially following the perimeter of the bottom but spaced therefrom, said pipe being provided with discharge means consisting of openings spaced along the length of the pipe which are directed toward the side Walls whereby substantially all of saidreturn. oil is discharged from the openings as streams which reach the tank Walls and are thereby cooled by conduction and which thereby also circulate the oil within the tank, an outlet pipe extending from the center of the tank and having an opening substantially in the same plane as said inlet pipe whereby the tank can be substantially tilted Without interfering with the continued fiow of oil through the tank, and a vent for. the tank positioned adjacent the center and top of the tank.

References Cited in the file of this patent UNITED STATES PATENTS Miller July 10, 1888 Marr Sept. 4, 1888 Kowalczuk Apr. 25, 1922 White Mar. 31, 1931 Lowen Aug. 16, 1932 Donnelly Nov. 3l0 1948 Goehring July 8, 1952 Crow Ian. 24,. 1956 FOREIGN PATENTS France Jan. 28,;1946 

